diff --git a/docs/schemas/storagepool.rng b/docs/schemas/storagepool.rng
index 2d165a3493..0f05c5cc5f 100644
--- a/docs/schemas/storagepool.rng
+++ b/docs/schemas/storagepool.rng
@@ -465,7 +465,7 @@
       <element name='format'>
         <attribute name='type'>
           <choice>
-            <value>auto</value>
+            <value>unknown</value> <!-- back-compat requires keeping 'unknown' not 'auto' -->
             <value>lvm2</value>
           </choice>
         </attribute>
diff --git a/docs/storage.html.in b/docs/storage.html.in
index 3d2ffcaafb..9933548f7c 100644
--- a/docs/storage.html.in
+++ b/docs/storage.html.in
@@ -328,14 +328,10 @@
 
     <h3>Valid pool format types</h3>
     <p>
-      The logical volume pool supports the following formats:
+      The logical volume pool supports only the <code>lvm2</code> format,
+      although not supplying a format value will result in automatic
+      selection of the<code>lvm2</code> format.
     </p>
-    <ul>
-      <li><code>auto</code> - automatically determine format</li>
-      <li>
-        <code>lvm2</code>
-      </li>
-    </ul>
 
     <h3>Valid volume format types</h3>
     <p>